Process for treating a sucrose syrup

ABSTRACT

The present invention provides a fractionation process for treating an aqueous sucrose syrup having, on a dry basis, an initial sucrose content of at least 30 w/w % comprising combining the syrup with a solvent selected from the group consisting of alkanols, ketones, and esters having 3 to 8 carbon atoms and mixtures thereof to form a system having at least two liquid phases in contact with a sucrose-containing solid phase and separating the phases, whereby there are obtained at least two products from the liquid phases, a first of which is characterized by a sucrose content, on a dry basis, greater than the initial content and a second of which is characterized by a sucrose content, on a dry basis, less than the initial content, in addition to a product obtained from the sucrose-containing solid phase.

This application is a 371 of PCT/GB97/03542 filed Dec. 24, 1997.

The present invention relates to a fractionation process for treating anaqueous sucrose syrup (hereinafter syrup). More particularly, thepresent invention relates to the treatment of an aqueous sucrose syruphaving, on a dry basis, an initial sucrose content of at least 30 w/w %.The syrups of interest are primarily those encountered in the cane sugarand beet sugar industries.

For the purposes of the present invention, these syrups will be treatedas consisting of water(W), sucrose(S) and non-sucrose(NS). This lastcategory comprises a large variety of chemical compounds originating incane sugar and in beet sugar, or formed during processing, and arepresent in variable amounts in syrups. These comprise, inter alia,carbohydrates other than sucrose, amino acids, proteins, inorganics etc.as reported extensively in the relevant literature. For the purposes ofthe present invention all of these are included within the term“non-sucrose”.

Two examples of typical compositions are listed below:

Syrup W S NS blackstrap molasses 17-25 30-40 35-53 affination syrup26-28 63-66 4-11

The carbohydrates in the non-sucrose (NS) fraction consist primarily ofglucose and fructose and are customarily referred to as “Invert”. Thisdesignation applies to (glucose+fructose), without implying that theseare necessarily in equimolar proportions. “Invert” will be used in thissense in the present specification.

In treating syrups for the purpose of upgrading their value throughfractionation, the recovery and distribution of the Invert between thefractions may represent an important feature of the process. Thus, sinceInvert is fully fermentable, it will be a desirable constituent ofsyrup-derived products directed to fermentation industries. It will be,however, an undesirable constituent of a syrup-derived product intendedfor further recovery of sucrose by evaporation, since Invert negativelyaffects sucrose crystallization. One of the useful aspects of theprocess is the capability it provides in recovering Invert-enriched andInvert-depleted products.

In the text and examples below, whenever figures for Invert (or forglucose and fructose separately), are given they should be understood asrepresenting part of the non-sucrose (NS) of the particular syrupdiscussed.

As is known, sugar in its purest (and most desirable) form consists of100% sucrose. In processing cane or beet for sugar the manufacturernaturally strives to approach complete recovery of sucrose in pure form.A large and costly part of processing consists of separating sucrosefrom non-sucrose by repeated crystallization of sucrose, pushing thenon-sucrose into successive mother liquors of increasing contents ofnon-sucrose which are syrups as defined above. Complete recovery ofsucrose by crystallization, however, is not feasible and sucrose ineconomically significant amounts inevitably reports to low valuemolasses. This in turn is sometimes subjected to a special separationprocess, such as chromatography over ion-exchange but the practice hasnot become universal due to marginal economics.

The foregoing indicates that a simple process to separate syrups intofractions that are either higher in sucrose content than the initialsyrup, or lower in sucrose content could be useful in sugar manufactureand refining as well as in molasses upgrading.

Elimination of non-sucrose from a syrup stream in a crystallizationsequence of sugar manufacture will obviously improve sucrose recovery.Such elimination need not be complete for the contribution to besignificant.

Molasses has uses in which its sucrose content is the main contributorto its value and other uses in which various non-sucroses (such asvitamins and amino acids) are the main contributor to its value.Fractionation of molasses could thus enhance its value by providingproducts that are tailored to specific end uses.

The present invention provides a simple and effective fractionation ofsucrose syrups as postulated above. It is based on the surprisingdiscovery that certain liquid compounds which, per se, are non-solventsof sucrose can be efficient solvents for the fractionation of syrups.Alkanols, ketones and esters were found to be effective compounds inthis respect. Particularly useful are alkanols, ketones and esters thathave in their molecule a total number of carbon atoms of three to eight.

Thus, according to the present invention, there is now provided afractionation process for treating an aqueous sucrose syrup having, on adry basis, an initial sucrose content of at least 30 w/w % comprisingcombining said syrup with a solvent selected from the group consistingof alkanols, ketones; and esters having 3 to 8 carbon atoms and mixturesthereof to form a system having at least two liquid phases in contactwith a sucrose-containing solid phase and separating said phases,whereby there are obtained at least two products from said liquidphases, a first of which is characterized by a sucrose content, on a drybasis, greater than said initial content and a second of which ischaracterized by a sucrose content, on a dry basis, less than saidinitial content, in addition to a product obtained from saidsucrose-containing solid phase.

The term “sucrose-containing solid phased” as used herein, refers to thefact that during and at the end of the fractionation process variedamounts of sucrose will be found in the solid phase, wherein at the endof the process said amount can be driven down to about 1%.

As will be realized, the present process provides a tool which enableseconomic decisions as to the amount of sucrose desired in each of thefinal phases.

In preferred embodiments of the present invention non-sucroseconstituents separate into an immiscible phase as described andexemplified hereinafter.

In another preferred embodiment of the present invention, at least oneof said phases is a solvent containing liquid phase, which phase isdehydrated to induce preferential precipitation of sucrose therefrom.

In, yet, another preferred embodiment of the present invention, theprocess is modified by re-combining two products, or more, into a singleproduct.

In especially preferred embodiments of the present invention saidsolvent is selected from the group consisting of alkanols, ketones,esters having between 3 and 6 carbon atoms and mixtures thereof.

The invention is best understood with reference to the systems formed bysucrose-water-solvent. These systems were found to have specific sharedfeatures that are described with reference to FIG. 1. appended hereto.

Therefore, the invention will first now be described in connection withcertain preferred embodiments with reference to the followingillustrative figure so that it may be more fully understood.

With specific reference now to the FIGURE in detail, it is stressed thatthe particulars shown are by way of example and for purposes ofillustrative discussion of the preferred embodiments of the presentinvention only and are presented in the cause of providing what isbelieved to be the most useful and readily understood description of theprinciples and conceptual aspects of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is an isotherm describing the case that water and solvent arepartially miscible at the selected temperature. This covers also thesomewhat simpler case of complete waterlsolvent miscibility.

In FIG. 1.:

c represents water saturated to solvent; d—solvent saturated to water;(c and d disappear in case of complete miscibility);

cefd is a 2-liquid phase region (that does not exist when completewater/solvent miscibility obtains);

a(water)ce and b(solvent)df are single liquid phase regions;

a (sucrose)ae and (sucrose)bf are regions of sucrose-containing solidphase and one liquid phase of which ae and bf are the saturation curves;

(sucrose)ef is the invariant region; any composition in this regionsplits into solid S and the two invariant liquid phases represented by eand f.

The terms “complete miscibility” and “partial miscibility” as used inconnection with the present invention characterize a solvent strictlywith respect to its behavior in systems that contain only the solventand water and with respect to a defined temperature. As is known,miscibility can change to non-miscibility and vice versa with change intemperature, or in the presence of a third component.

The co-existence of two liquid phases in equilibrium with solid sucroseover wide temperature ranges is a feature that characterizes all thecompounds defined as “solvent” with respect to the present invention.Furthermore, these regions are quite large rather than negligibly smallas might have been expected from the fact that sucrose is virtuallyinsoluble in compounds claimed as solvents by the present invention.This unexpected aspect of sucrose syrups solubility behavior is broughtout in the following table, which provides the invariant compositions eand f for several solvents at 40° C. and 700° C.

TABLE 1 40 C. 70 C. Solvent solvent sucrose water solvent sucrose waterMe₂CO light 76.6 2.5 20.95 invariant phase Me₂CO heavy 13.85 57.55 28.6invariant phase iPrOH light 67.2 11.4 21.4 73.1 9.55 17.35 invariantphase iPrOH heavy 8.7 59.2 32.1 7.85 70.2 22.05 invariant phase nPrOHlight 78.5 4.8 16.7 78.65 6.45 14.9 invariant phase nPrOH heavy 4.3 65.929.8 5.9 70 24.1 invariant phase iBuOH light 89.65 0.65 9.65 89.6 1.45 9invariant phase iBuOH heavy 2.1 67.9 30 2.1 73.15 24.35 invariant phasenBuOH light 87.05 0.95 12.1 88.7 1.7 9.7 invariant phase nBuOH heavy 2.168.8 28.1 2.2 72.4 25.4 invariant phase EtOAc light 95.8 0.765 3.435 941.44 4.35 invariant phase EtOAc heavy 2.4 69.1 28.5 0.5 76.1 23.4invariant phase nPrOAc light 96.5 0.175 3.35 95.3 0.095 4.6 invariantphase nPrOAc heavy 0.5 70.9 28.6 0.3 77 22.7 invariant phase

As can be clearly seen from Table 1, the light invariant phase and theheavy invariant phase in equilibrium provide completely novel means ofdistributing sucrose between liquid phases. The compositions of thesetwo equilibrium liquid phases, for the solvents considered, are uniqueand novel. Nothing in prior art could teach the selectivities withrespect to sucrose nor the sucrose distribution between these liquidphases. The same applies to non-sucrose compounds commonly found insyrups and their distributions relative to sucrose. All that an engineerwould need for this purpose are one or a few isotherms that, if notcomprised in the table above, are easy to establish experimentally.

A particularly useful feature of a large invariant zone is that itprovides for a predictable distribution of sucrose between asucrose-containing solid phase and two liquid phases by means of asingle operation consisting of mixing the syrup with a calculated amountof solvent and allowing the phases to separate. Naturally, non-sucroseconstituents present in a sucrose syrup will also distribute between thephases and thereby change their compositions, however the referencesystem water-sucrose-solvent provides a guide that allows to determinean optimal procedure by a few experiments.

In a preferred embodiment of the present invention, the process can befurther refined and modified to comprise combining said syrup with saidsolvent to form a system having at least two liquid phases, separatingsaid phases and combining at least one of said phases with additionalsolvent to form therefrom a system having at least two further liquidphases, separating said further phases and removing said solventtherefrom, whereby there are obtained at least two products from saidliquid phases, a first of which is characterized by a sucrose content ona dry basis greater than said initial content and a second of which ischaracterized by a sucrose content on a dry basis less than said initialcontent.

A further interesting feature of these solvents is that they form withglucose and with fructose systems which are generally similar to thosewhich they form with sucrose analogous to the phase diagram of FIG. 1.As for sucrose, the solubilities in dry solvents are low. However, bothglucose and fructose (or more generally, Invert as encountered inindustrial sugar recovery and refining), are more soluble than sucrose.This distinguishing feature of Invert vs. Sucrose provides forseparation and recovery options between these two components.

It is noteworthy that an invariant zone for the systemwater-sucrose-acetone was already observed in 1904 and the isotherm for25° C. was described in detail by W. Herz & al in Z. Anorg. Chemie, 4A1p.309, 1904 and has been reproduced in the common handbook Seidell,Solubility of Inorganic and Organic Compounds the first edition of whichdates to 1907. A literature survey found no continuation of this line ofinvestigation with respect to other solvents. As the review of prior artfurther below indicates, inventors claiming solvent-based processes forsyrup purification failed to use the potentialities of the invariantzone even with acetone as solvent.

Sugar manufacture is an old industry of over 200 years. Recordedproposals to use solvents in the operations of this industry arerelatively few and none has become established practice. The presentinvention differs fundamentally from these proposals as will be realizedfrom the following brief review of relevant prior art patents.

Paulsen (U.S. Pat. No. 26,050 of 1859) proposes the use of ethanol/watermixtures as a solvent to dissolve sucrose and reject non-sucroseconstituents (and thereby facilitate recovery.

Clarke (U.S. Pat. No. 5,454,875 of 1995) also proposes the use of EtOHto precipitate impurities from molasses in combination with additionaloperations.

Othmer (U.S. Pat. No. 4,116,712 of 1978) also proposes the use ofethanol as the key component in ethanol/acetone mixtures proposed assolvent for the extraction of impurities.

Thus, over a span of some 150 years, ethanol has been considered as asolvent of choice and ways were sought for its application ineconomically effective way—unsuccessfully.

The system water-sucrose-ethanol does not form an invariant zone at anytemperature studied thus far. At any given temperature the solubility ofsucrose in water-ethanol mixtures decreases as the ratio of ethanol towater increases. This decrease of solubility is perfectly continuousfrom 0% to 100% of EtOH in the EtOH/water mixture. For this reason,ethanol, which has been suggested as the solvent of choice in the priorart patents is totally distinguishable from the solvents of the presentinvention in that, as describe and claimed herein, the solvents used inthe present invention, constitute systems characterized by extensiveinvariant zones.

While ethanol as used in the prior art does permit the selectiveprecipitation of inorganics and some non-sucrose organics, this requiresa proportion of ethanol to water of at least 1.2:1 (see Clarke). Thusthe syrup of Ex.1 hereinafter, containing 21.3% water, would require theaddition of some 30 grs ethanol per 100 grs syrup to achieve resultssimilar to those obtained by means of just 7 grs nPrOH. Obviously,further separation, such as described in examples 3 to 7 hereinafter,are inherently impossible with ethanol.

It is interesting to note that Othmer in U.S. Pat. No. 4,116,712 issuedin September of 1978, reviews the state of the prior art as follows:

“For many years sugar refiners have tried to use ethanol in theaffination of raw sugar without success, and for the liquid-liquidextraction of other solids, i.e. various impurities, away from a sugarsyrup in a final molasses.

For example, Vazquez in U.S. Pat. No. 2,000,202 treated a concentratedmolasses with a nearly anhydrous ethanol mixed with a second liquid suchas ethyl acetate. This combination dissolved the impurities andprecipitated or crystallized the sugar out in a mass or massecuite ofcrystals. The alcohol and impurities were removed as an extract molassescontaining the impurities; and the sugar crystals were then laterdissolved with more dilute alcohol from the insoluble impurities whichremained.

Alcohol has been found to be a poor solvent for many of the impuritieswhile it is, as noted in Vazquez, when somewhat diluted, a good solventfor the sugar—thus no industrial use has been reported of systems baseon its use as: (a) an afination solvent, (b) an extraction liquid forimpurities from a syrup or molasses, or (c) for precipitating crystalsof sugar and washing them, then dissolving them as suggested in U.S.Pat. No. 2,000,202.

Bohrer U.S. Pat. No. 3,174,877 used methanol with 1 to 5% of ahydrocarbon to decolorize raw sugar in an affination, and showed thatethanol was definitely unusable for this purpose. His solvent was notchosen to remove other impurities of raw sugar, with which U.S. Pat. No.3,174,877 was unconcerned.

Leonis U.S. Pat. No. 1,558,554 dried molasses and treated this withglacial acetic acid for 2 to 24 hours during which time the impuritiesevidently went into solution, the sugar was precipitated; and theimpurities remained in the mother liquid.

Othmer U.S. Pat. No. 3,325,308 washed sugar crystals with pure methanolor pure acetic acid, separated the impurities in an extract molasses,removed the solvent therefrom; and then, out of this molasses, extractedwith acetone the oils, fats and waxes for which the acetone has anexcellent selectivity.”

Seventeen years later, Clarke, in U.S. Pat. No. 5,454, 875 issued inOctober 1995, reviewed the state of the art as follows:

“U.S. Pat. No. 5,002,614 describes a process for extracting cane waxfrom molasses with an alcohol solvent.

U.S. Pat. No. 4,116,712 describes a process for removing impurities fromsugar crystals and syrups by a liquid/liquid phase extraction using amixture of two solvents, with at least part of the extraction operationpreferably being conducted at a pH of 1.25 to 1.30. The preferredsolvents are ethanol or acetic acid in combination with acetone. Afterextractions time and later carbon dioxide may be added to adjust the pH.

U.S. Pat. No. 3,876,466 discloses reducing the viscosity of a sugarsolution by adding aromatic organic sulphonic acids, their orderivatives.

U.S. Pat. No. 3,781,174 discloses the production of refined sugar fromraw cane juice by continuous carbonation, with active carbon and acombination of ion-exchange resins and ion-xchange membraneelectrodialysis.

U.S. Pat. No. 3,734,773 discloses the purification of sugar beetdiffusion juice, with recovery of certain organic acids as a by-product,in which carbon dioxide or carbonate ions in hot water are used toprecipitate calcium carbonate.

U.S. Pat. No. 3,563,799 discloses the purification of dilutesugar-containing liquids by concentration of the liquid,demineralization in a mixed resin ion-exchange; further concentration,and filtration.

U.S. Pat. No. 3,325,308 discloses the removal of impurities from rawsugar with three successive solvent extraction systems. Methanol is thepreferred first solvent, acetone the preferred second solvent, and waterthe preferred third solvent.

U.S. Pat. No. 2,640,851 discloses the recovery of alkaline earthaconitates from blackstrap molasses through a process using the additionof lime and calcium chloride at high temperatures.

U.S. Pat. No. 2,379,319 discloses the removal of impurities from sugarbeet diffusion juice by treatment with a proteolytic enzyme, followed byaddition of lime and carbonate.

U.S. Pat. No. 2,043,911 discloses the removal of sulphite impurities andadded during the manufacture of sugar by adding an oxidizing agent.

U.S. Pat. No. 2,000,202 discloses the recovery of sugar from molasses byadding ethanol and sulphuric acid to remove organic acids, followed byprecipitating the sugar with another organic solvent, such as ethylacetate.”

As will be realized, none of said references taught or suggested thepresent fractionation process based on the use of the solvents definedherein for treating an aqueous sucrose syrup, to form a system having,at least, two liquid phases in contact with a solid sucrose phase andthe advantages obtainable therewith.

It has also surprisingly been found that the addition of solvent tosyrup in amounts just sufficient to induce the formation of two liquidphases can already serve a very useful purpose by precipitatingnon-sucrose constituents. The separation of such precipitates from thesaturated aqueous phase, just saturated by solvent, is easy and canresult in a useful separation, per se, as well as result in significantupgrading of the products obtained in subsequent manipulations of thesyrup according to the present invention, whereby products richer insucrose than the starting syrup and products poorer in sucrose than thestarting syrup are obtained.

The invention makes it possible to separate dextrose and fructose, fromsucrose with surprising simplicity. Dextrose and fructose are frequentlylumped under the name of “Invert” in the sugar industry withoutnecessarily designating an equimolar mixture. This name will also beused herein as a matte of convenience. At present such separation isgenerally achieved laboriously by multiple crystallizations—a major costin sucrose production. The difficulties of separations between dextrose,fructose and sucrose have always been understood and explained as due tothe similarities between these carbohydrates. The ease of achieving asubstantial separation by the present invention was thus totallyunexpected.

Thus, in a preferred embodiment, the present invention also provides afractionation process, as herein defined, wherein the ratio of invert tosucrose in one of the liquid phases is lower than in the syrup treatedand the ratio of invert to sucrose in the other liquid phase is higherthan in the syrup treated.

While the invention will now be described in connection with certainpreferred embodiments in the following examples so that aspects thereofmay be more fully understood and appreciated, it is not intended tolimit the invention to these particular embodiments. On the contrary, itis intended to cover all alternatives, modifications and equivalents asmay be included within the scope of the invention as defined by theappended claims. Thus, the following examples which include preferredembodiments will serve to illustrate the practice of this invention, itbeing understood that the particulars shown are by way of example andfor purposes of illustrative discussion of preferred embodiments of thepresent invention only and are presented in the cause of providing whatis believed to be the most useful and readily understood description offormulation procedures as well as of the principles and conceptualaspects of the invention.

EXAMPLE 1

A syrup (1) internal to cane sugar refining had a very dark color andthe composition tabulated below.

Solids Water 78.7 21.3 100 Solids (dry basis) Sucrose Non-sucrose 85.814.2 Invert Non-carbohydrates 7.4

100 grs of (1) were mixed at 40° C. with 4 grs nPrOH; the mixture waspoured into a graduated cylinder and had the volume of 92 ml; there wasno evident separation of solids visible; the material was remixed withadditional 3 grs of nPrOH whereupon the separation of abundant solidswas in evidence and when allowed to stand for a time it settled into alower dark slurry layer and an upper light-colored layer above which avery small ring of an even lighter solvent layer was just visible. Afterseparation of the bottom layer from the aqueous layer above it (togetherwith the minor solvent layer) and removal of the nPrOH by distillation,a dark colored syrup and a light colored syrup were obtained, which, ona dry basis, contained respectively 24% of total solids at 72.2% sucroseand 76% of total solids at 90.2% sucrose.

EXAMPLE 2

100 grs of blackstrap molasses was mixed with 6 grs nBuOH at 90° C.,allowed to settle, separated and desolventised to obtain two productswhich, on a dry basis, were about equal in weight and contained 23%sucrose and 47% sucrose, respectively.

EXAMPLE 2a

100 grs of the same molasses as used for Example 2 were contacted with400 grs solvent consisting of 320 grs n-propanol and 80 grs water at 80°C., as in the first contact and the solvent layers combined.

The combined solvent layers were contacted with 10 grs active-carbon andfiltered, whereby they turned from a very dark color to light-brownliquid. After distillation of the solvent, a honey-brown syrup wasobtained. It contained 95% of the invert and 82% of the sucrose in themolasses, subjected to this two-stage cross-extraction.

EXAMPLE 2b

The same as Example 2a only instead of 5 grs active carbon, thetreatment was made by 10 grs of Fuller earth (such as commonly used inthe oil industry). Decolorisation nearly equal to that of active carbonwas achieved.

EXAMPLE 3

100 grs of the same syrup as in example 1 were treated at 75° C. withnPrOH in a two step operation. The first step was mixing with thesolvent separated in the second step and then the settled layer fromthis step was mixed, in a second step, with Bgrs nPrOH and separated.The upper layer from the first step and the bottom layer of the secondstep were desolventised into a light and dark products respectively. Thecompositions of the products of Examples 1&3 are compared, on a drybasis, below.

Product % of total % sucrose % non-sucrose Exs. 1, light colored 76 90.29.8 Exs. 1, dark colored 24 72.2 27.8 Ex. 3, light colored 85.2 91.7 9.3Ex. 3, dark colored 14.8 52 48

EXAMPLE 4

100 grs of the same syrup as in Ex.3 were treated as in Ex.3 with thedifference that the light colored liquid phase, separated from the firstmixing operation, was mixed with a further 80 grs of nPrOH at the sametemperature. An abundant white precipitate formed, which was filtered,and which on analysis was found to consist of virtually pure sucrose. Onremoval of solvent the three fractions collected were as shown in thefollowing table:

Ex. 4 Product % of total % sucrose % non-sucrose dark coloredprecipitate 14.8 52 48 light colored precipitate 51.3 >99 <1 lightcolored solvent phase 33.9 80.5 19.5

EXAMPLE 5

100 grs of the same syrup used in the previous example were mixed with 5grs nBuOH at 80° C. and the mixture was centrifuged. A dark solid masssettled in which one could perceive sucrose crystals. The solids wereseparated from the liquid phase, re-slurried with 100 nBuOH andseparated by centrifugation and the solvent phase mixed with the liquidphase of the previous operation. Three easily perceived phases formed: anearly colorless solid sucrose, a heavy aqueous phase and a lightsolvent phase (the latter two deriving obviously from the invariantphases of the corresponding water-sucrose-nBuOH system). The aqueouslayer containing the solid sucrose is separated as a single product fromthe solvent phase. After desolventising the amounts and compositions ofthe three fractions were as shown in the following table:

Ex. 5 Product % of total % sucrose % non-sucrose 1^(st) precipitate,dark colored 11.4 36 65 2^(nd) precipitate + aqueous 80 98 2 phase,light colored Residual product, light colored 8.6 22 79

EXAMPLE 6

The solvent layer obtained in Ex.4 is desolventised in two stages. Inthe first stage water is removed by distilling out a water/nPrOHazeotrope. Sucrose which has a very low solubility in nPrOH, and a lowsolubility in all of the “solvents” of the present invention,precipitates and is collected. After desolventising, the light coloredsolvent that contained 33.9% of total solids provides, 25% of solidsat >99% sucrose, and 8.9% of solids at about 26% sucrose, 84% beingsubstantially Invert.

The foregoing examples demonstrate the versatility, which the presentprocess provides, for fractionating syrups into products varying insucrose contents, as well as in the nature of the non-sucrose. The widerange of temperatures and the choice of solvents provide also foroptimization of recoveries, savings in energy etc. that will be obviousto the practicing technician.

The comments below with regard to the above examples and theramifications thereof, illustrate this point.

In Example 1 the precipitate contains primarily “Ash”, a term in commonuse in the industry to refer generally to inorganics andnon-carbohydrate organics as the non-sucrose components since the Invertaccompanies the sucrose into solution and is in fact more soluble in thesolvents than sucrose itself;

Example 2 illustrates that by choice of temperature and of solvent it ispossible to determine the amount of solvent employed as well as otherobvious factors. Thus, e.g., in the present case, the higher temperaturelowers the viscosity of the highly viscous molasses thereby providingfor operational requirements;

Examples 2a and 2b illustrate decolorising solvent extracts so as toobtain light-colored syrup products. This is advantageous sincedecolorising syrups directly is impractical;

Example 3 introduces a counter-current operational feature therebyachieving a higher recovery of sucrose than in the former two examplesand also a better separation between Ash and Organics (that accompanythe dark fraction) and Invert—that accompanies the sucrose;

Example 4 illustrates separations achievable by a succession of adjustedadditions of solvent. In fact, the described operation can be furtherextended to achieve considerable separation between sucrose and Invertas described in Example 6 above.

Example 5 achieves approximately the results of Example 4 and Example 6combined by the use of nBuOH rather than nPrOH and a higher operationaltemperature.

It will be evident to those skilled in the art that the invention is notlimited to the details of the foregoing illustrative examples and thatthe present invention may be embodied in other specific forms withoutdeparting from the essential attributes thereof, and it is thereforedesired that the present embodiments and examples be considered in allrespects as illustrative and not restrictive, reference being made tothe appended claims, rather than to the foregoing description, and allchanges which come within the meaning and range of equivalency of theclaims are therefore intended to be embraced therein.

I claim:
 1. A fractionation process for treating an aqueous sucrosesyrup having, on a dry basis, an initial sucrose content of at least 30w/w % comprising combining said syrup with a solvent selected from thegroup consisting of alkanols and esters having 3 to 8 carbon atoms andmixtures thereof to form a system having at least two liquid phases incontact with a sucrose-containing solid phase and separating said phasesinto at least one solvent phase and at least one aqueous phase, wherebythere are obtained at least two products from said liquid phases, afirst of which is characterized by a sucrose content, on a dry basis,greater than said initial content and a second of which is characterizedby a sucrose content, on a dry basis, less then said initial content, inaddition to a product obtained from said sucrose-containing solid phase.2. A fractionation process according to claim 1 in which said solvent oradditional solvent is n-propanol.
 3. A fractionation process accordingto claim 1, wherein non-sucrose constituents separate into an immisciblephase.
 4. A fractionation process according to claim 3, in which saidsolvent or additional solvent is n-propanol.
 5. A fractionation processaccording to claim 1, wherein said solvent is selected from the groupconsisting of alkanols having between 3 and 6 carbon atoms and mixturesthereof.
 6. A fractionation process according to claim 5, in which saidsolvent or additional solvent is n-propanol.
 7. A fractionation processaccording to claim 1, wherein said solvent is removed from a separatedliquid phase by distillation.
 8. A fractionation process according toclaim 7, in which said solvent or additional solvent is n-propanol.
 9. Afractionation process according to claim 1, wherein the ratio of invertto sucrose in said aqueous phase is lower than in the syrup treated andthe ratio of invert to sucrose in the said solvent phase is higher thanin the syrup treated.
 10. A fractionation process according to claim 9,in which said solvent or additional solvent is n-propanol.
 11. Afractionation process according to claim 1, comprising combining saidsyrup with said solvent to form a system having at least two liquidphases, separating said phases and combining at least one of said phaseswith additional solvent to form therefrom a system having at least twofurther liquid phases, separating said further phases, whereby there areobtained at least two products from said liquid phases, a first of whichis characterized by a sucrose content on a dry basis greater than saidinitial content and a second of which is characterized by a sucrosecontent on a dry basis less than said initial content.
 12. Afractionation process according to claim 11, in which said solvent oradditional solvent is n-propanol.
 13. A fractionation process accordingto claim 1, wherein at least one of said phases is a solvent containingliquid phase, which phase is dehydrated to induce preferentialprecipitation of sucrose therefrom.
 14. A fractionation processaccording to claim 13, in which said solvent or additional solvent isn-propanol.
 15. A fractionation process according to claim I comprisingrecombining said at least two products into a single product.
 16. Afractionation process according to claim 15, in which said solvent oradditional solvent is n-propanol.